Improvement in sewing-machines



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A. `1. lw. ROBERTSON..

Patented Oct. 25, 1859.

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Patented Oct. 25, 1859.

(Wl/Nrw? MQ@ UNITED STATES PATENT OFFICE.

T. 177W'. ROBERTSON, OF NEV YORK, N. Y.

IMPROVEMENT IN SEWING-MACHINES..

Specification forming part of Letters Patent No. 25,913., dated October25, 1859.

To all whom it may concern:

Be it known that I, T. J.' XV. ROBERTSON, of the city, county, and Stateof New York, have invented certain new and useful Improvements inSewing-Machines; and I do hereby declare that the following is a full,clear, and exact description of the same, reference being had to theaccompanying drawings, forming part of this specification, in which-4Figure l is a front view of my improvement. Fig. 2 is a side view withpart of the frame removed, as shown by the dotted line c bin Fig. 1.Fig. 3 is a plan of that part of the machine below the line Vc d in Fig.2. Fig. 4 is a plan showing the under needle in a different position tothat in the last gure.V Fig. 5 is a magnified view of part of the twoneedles used.

Similar letters of reference indicate corresponding parts in the severalfigures.

To enable others skilled in the art to which this pertains to make anduse my invention, I

' .T and vibrating arm K.

L is another vibrating arm, also attached to rock-shaft I, carrying apeculiarly formed piece of steel, M, whose precise shape will beunderstood by reference to Figs. 2 and 4. in the annexed drawings. Thispiece M may be called a needle-carrier, 7 as the under needle, N, isattached to it by the screw e, (or, if preferred, the said needle N andcarrier M may be made in one piece.)

O is a small rock-shaft working in bearings f g in arm L, and is screwedinto the needlecarrier M, allowing said needle-carrier and needle tohave a vibratory motion.

Q is a plug inserted into a socket, It, in the frame A, havinga spring,S, around it, said spring having a tendency to press the plug Q, out ofthe socket and against the side of the needlecarrier M.

T is another spiral spring on rock-shaft I, exerting its force in suchamanner as to carry the said rock-shaft I in the direction ofthe path ofthe vertical needle C. To limit its motion in this direction I use aguide, U, which fits into a groove, i, turned in the rock-shaft I. Thisguide U is governed and held in its place by a screw, j. The obj ect ofthis device is the easy adjustment of the under needle, N, so that bysimply turning the screw j the said under needle may be placed nearer toor farther from the vertical needle O.

' V is a spring take-up for keeping the under thread taut, so that thevertical needle will be sure to take a loop from the under needle, N.This take-up is formed by winding the wire of which it ismade in aspiral form. This enables me to make a more jiiexible take-up than canbe constructed in any Vother manner. It is attached to the vibrating armL by a screw, k,- which yserves also as a thread-guide for the underthread.

XV is the table or platform of the machine, which is loosely fastened toone side of the frame A by a screw, Z, allowing it to turn easily, sothat it maybe removed in the manner-shown in Fig. 3 for threadingtheneedle and other purposes. The table i`s kept in its proper place, whenrequired, by the pin X, which passes through a lug, m, on the under sideof the table WV into the frame A, as seen in Fig. 1. The thread of thevertical needle is represented in blue, and that of the under needle inred.

The operation of the parts in inter-looping follows: The cloth Y havingbeen placed on the table XV, the needle C is caused to descend, carryingwith it aloop of thread. As it begins its return motion the underneedle, N, advances toward itand enters the loop formed in the thread ofneedle C, carrying with it a loop of its own thread, and the two needlesassume the various relative positions shown in Figs. l, 3, and 5. Whenthe under needle has reached the position shown in red outline in Fig.8, the plug Q advances, asseen (also in red) in the same figure. As theneedle C again descends the under needle, N, retreats, and. theprojection o on the carrier M, coming in contact with the plug Q, causesthe needle N to cross the path of the vertical needle C, so as to openthe loop of the under thread, as

the two threads together may bel described as Y seen in Fig. 4.' As theneedle N continues to recede the carrier M slips off the plug. Q, (theVertical needle C having taken the loop,) and is carried back to itsoriginal position by the spring P. Thus it will be seen that each needletakes a loop from the other needle, and if the fabric to be seWed ismoved the necessary distance to form a stitch by any suitable meansbetween each movement of the needles, a line of stitching will be formedlike that known as the two-thread chain or double look 7 stitch.

Should it be necessary to use foot or other power to operate themachine, a pulley may be substituted for the crank H.

By a slight change in the form of the neo carrier M, `spring-plug Q, andvibrating arm L, substantially as and for the purposes herein shown anddescribed.

June 1, 1859.

T. J. XV. ROBERTSON. Vitnesses z W. TUsoH, E. Wonrn.

